Synthesis of substituted 2,2′-bipyridines and 2,2′:6′,2"-terpyridines by cobalt-catalyzed cycloaddition reactions of nitriles and α,ω-diynes with exclusive regioselectivity
Synthesis of substituted 2,2′-bipyridines and 2,2′:6′,2"-terpyridines by cobalt-catalyzed cycloaddition reactions of nitriles and α,ω-diynes with exclusive regioselectivity
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DOI：
10.1002/adsc.200700380
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发表时间：
2008-01-01
影响因子：
5.4
通讯作者：
Okamoto, Sentaro
中科院分区：
文献类型：
--
作者：
Goswami, Avijit;Ohtaki, Kazuhiko;Okamoto, Sentaro
在锌催化下，1，2-二（二苯基膦基）乙烷（dppe）/六水氯化钴（COCl 2中心点6 H（2）O）/二炔与亚硝酸酯的[2+2+2]环加成反应，合成了一系列取代的2，2 '-联吡啶，所有反应均表现出独特的区域选择性.因此，对称和不对称的1，6-二炔和2-氰基吡啶在5mol%的dppe、5mol%的COCl 2中心点6 H（2）O和10mol%的锌粉存在下反应，得到相应的2，2 ′-联吡啶。在相同的反应条件下，1-（2-吡啶基）-1，6-二炔与亚硝酸酯反应平稳，具有独特的区域选择性，以较高的产率生成2，2 '-联吡啶。通过1，6，8，13-四炔与腈的[2+2+ 2]双环加成反应，得到了2，2 '-联吡啶。类似地，从1-（2-吡啶基）-1，6-二炔和2-氰基吡啶合成2，2 '：6'，2”-三联吡啶。所观察到的区域化学可以通过考虑钴环戊二烯中间体和亚硝酸盐的电子性质来解释。独家区域化学趋势的调查提供了合理的可信度，本方法的合成潜力。
A variety of substituted 2,2'-bipyridines were synthesized by a 1,2-bis(diphenylphosphino)ethane (dppe)/cobalt chloride hexahydrate (COCl2 center dot 6H(2)O)/zinc-catalyzed [2+2+2]cycloaddition reaction of diynes and nitrites, with all reactions exhibiting exclusive regioselectivity. Thus, symmetrical and unsymmetrical 1,6-diynes and 2-cyanopyridine reacted in the presence of 5 mol % of dppe, 5 mol % Of COCl2 center dot 6H(2)O and 10 mol % of zinc powder to provide the corresponding 2,2'-bipyridines. Under identical reaction conditions, 1-(2-pyridyl)-1,6-diynes and nitrites reacted smoothly with exclusive regioselectivity,to produce 2,2'-bipyridines in good yield. 2,2'-Bi- pyridines were also obtained by the double [2+2+ 2] cycloaddition reaction of 1,6,8,13-tetraynes with nitriles. Similarly, 2,2':6',2"-terpyridines were synthesized from 1-(2-pyridyl)-1,6-diyne and 2-cyanopyridine. The regiochemistry observed can be explained by considering the electronic nature of cobaltacyclo-pentadiene intermediates and nitrites. A survey of the exclusive regiochemical trend gives reasonable credence to the synthetic potential of the present method.